Underground electric cable



June 2, 1936. P. T. cAPDEvlLLE UNDERGROUND ELECTRIC CABLE Filed Aug. 15, 1934 lNVENTR ATTORNE) Patented June 2, 1,936

PATENT OFFICE l UNDERGROUND ELECTRIC CABLE Pierre Thodore Capdeville, Nogent-sur-Marne, France, assigner to Trelcries d; Laminoirl du Havre, Paris, France Application August 15, 1934, semina. '139,995 l In France August 25, 1933 The invention relates to underground electric cables of the type comprising a stranded conductor which is applied over a hollow core whose internal duct is filled with oil or other liquid insulation. .The conductor is coveredby an, insulating substance, for instance paper, which is impregnated with oil or other liquid insulation and around which is an hermetical lead sheath.

In cables oi' this kind, the oil which iills the central duct or channel o f the core and which wets the metal conductors and impregnates the insulating substance is kept at a suitable pressure by means of oil containing reservoirs. When,- under the inuence oi' current ilow, the cable becomes heated, the oil which it contains expands, and a certain quantity of oil llows into the reservoir. Inversely, when the cable cools, the oil which it contains contracts, and the reservoir discharges oil into the cable, consequently, the latter'is always full of oil under pressure.

When the cable is very long, it is advisable to subdivide it into several sections, each provided with special oil reservoirs, in order to avoid: ilrst,

in an inclined cable section, too high a hydrostatic pressure at the low points ot'that section; second,'in extensive horizontal cable sections, too considerable a. longitudinal displacement of liquid between the central canal or duct andthe iilled reservoirs.

In order to connect two-consecutive sections with each other, a device is used called a stop joint, which insures the electrical continuity and also the insulation with respect to ground. of the various parts that are inter-connected but which forms a stop between the oil contained in one section and the oil contained in the adjacent section. This joint makes it possibleto connect oil reservoirs to both sides of the joint so as to feed with oil two adjacent sections. The object of the invention is the provision of a stop joint of improved and simplified construction. j

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto. l

In the attached drawing, which is illustrative of my invention, Fig. 1 is a longitudinal section vof a stop joint and Fig. Zis an exploded view of the connector members or parts. l The stop joint which is shown in the drawing comprises an hermetically sealed metal envelope constituted by a cylindrical body I connected through the intermediate caps 2, I, 4 and 5 to.

the lead sheath of the two cables 0 and 1 which 1 erations are covered with bands Il for the same are to be interconnected. These various parts are secured to each other through wipe soldering.

The insideof the casing is subdivided .into two chambers, a large one 24 and a small one 25, by means of an oil-impervious 'insulating tube l, a Il hollow metal sleeve 9, and\the various connecting parts which are suitably` insulated with respect to especially the insulator 8.

The electric continuity oi the cable is insured by the socketed connector member III which is secured to the stranded conductor II and by the other member to be referred to later. mounting the connector member in place, a iew of the end turns of the open lielix I6, located within the stranded conductor for supporting it are removed, and for the turns so removed is substituted a steel tube 21 which acts as support for 25 conductor I I during the compressing of the connector member I0. The tube has a flanged head which engagesthe ends oi the conductor strands and also the bottom oi the socket formed in the member lo. The wan of. the socket is tightly 3 squeezed against the conductor I I by the use of a suitable press, and the groove lI 2 which has been formed during that operation is covered by a metal ring I5, so as to present a smooth unbroken exterior an'd thus avoid concentration of electrical stresses.

Formed integral with 'the connector member I0 is a cylindrical extension or rod I3 which extends into and is seated in a socket formed in a second connector member I4, said rod and socket being 4 in telescopic relation. The part I3 may have longitudinal grooves; as shown, the walls of which assist in m ing a good electrical joint. 'I'he second connector member and rod are united by compressing or ,squeezing the former on the latten 4 In the right hand end of the secondy connector member is 'a socket yinto 'which is fitted the end of conductor I1, and these parts are also united byA compression. The grooves formed in such opreason as before. f

In this manner, conductors and connecting parts are iitted together in succession and very good electric conductivity attained betweeny the various parts.

Prior to v20.

` casing, as well as theirinsulation in a longitudinel direction.` 'I'he insulating sleeve or tube 8 is supported on the inside by a tubular metallic support 8* which also .acts as a shield. It will be noted that the right hand end of the tube is located between two opposed cylindrical surfaces so that itis well supported. This permits the use of a thinner insulation than would otherwise be allowable. The joints between the parts emay be made iiuld tight by any suitable means,

as for example by rst coating the adjacent suriaces with metall and then soldering them. The

outer end of the insulating tube 8 being supported Openings, for instance 36, are provided in. the l by the metal ring I8, may be united with it in the same manner.`

Around the connector I4 and the sleeve 9 are wound bands I9 consisting of .a fibrous material which is impregnated with oil and whichinsures y'the insulation oi' themembers I0 and. Il and sleeve 9 with respect to a metal cylinder 20, the latter being connected by means or the metal ribbon 2I to the lead 4oi .the cable 1 and to ground.

cylinder zu, and' au the cavities within that metal cylinder are lled with oil under pressure.

Each one of the ends of cables 6 and l has its lead sheath removed'and is wrapped with paper tapes 22 and 23 over the factory applied insulation, allowance being made'ior extra thickness, the paper tapes being themselves covered with metal electrostatic shields and 35, to distributey the electrical stresses, said shields being grounded `to the lead sheaths by clamps 3.49.

The' iiow oi oil between the outer chamber 24 and the inner left hand chamber 25 is prevented as'follows: The caps 3 and 4 of the casing are iltted and soldered to collar I 8. The tube 8 which is insulating and impervious to oil is secured hermetically to the ring o'r collar I8 and to the metal sleeve 9. The connector member Il which is screwed and soldered to sleeve 9 has' a transverse wall 26 so that oil cannot iiow fromchamber 2l to chamber 25, and vice versa.' i

On 'the other hand, the hollow core of cable 9 communicates with the left hand chamber 25 by means'oi' the steel tube 21 and by the recess 28 and port 28n in connector I0. In this manner, the oil can flow from the central channel of the conductor II to the chamber 25, and vice versa.

Likewise, cable. 'I has a steel tube 29 which communicates with the connector I4. The cen- ;tral portion o! the connector has a recess 30 and a lateral port 30e. The port communicates with Athe helicoidal conduit 3'I4 which is made by windinga relatively thick paper tape 3| around the connector I4 and insulation thereon so that .it forms a longopen helix of restricted cross-sectional area. As a result of this conduit and ot holes'l, oil can ilow from conductor I to chamber 2l, and vice versa.

`Pipe connections 32 and 33 between the chambers 2l' and 25 and reservoirs (not shown) make it possible independentlyv to supplyv with oil the two adjacent sections constituted by the cables 6 and 1. One of the advantages of my improved construction resides in the fact that it is shorter than other Joints for the same purpose and hence smaller manholes may be used, and being shorter takes less material with a corresponding reduction in cost.

Such a Joint as described herein can be assembled in a very simple manner at the place of in- 6 stallation oi the cables. The only insulation which must be provided consists of-tape made of fibrous material wrapped around the conducting bodies, as is customary with normal joints.

A further and material advantage of my improved constructidn resides in the fact that it is substantially shorter thanother constructions intended for the same purpose. This is due chiefly to the i'act that only one preformed insulator, such as 8, has to be 'provided which is in telescopic relationto the socket of the connector part enclosed thereby. This latter arrangement permits of supporting the inner end of the insulator not by the connector which it surrounds but by the second connector member. in this case through the medium oi sleeves 9 and 9. The reduction in length i' the joint is duenot only to the absence of the second insulator but to the elimination oi the space required for the connectingmeans between adjacent ends of the insulators.

Itis tobe understood that the invention is n ot limited in all respects to the arrangement which has been shown in the drawing by way of example, 'and that modiiications of details may be applied.

What I claim as new and desire to secure by Letters Patent of the United States isz- 1. In a cable joint of the character described, the combination of a pair oi' conductors arranged end to end, each having a central fluid illled channel, means for electrically'uniting the con-I ductors and interrupting the passage of uid from one channel to the other, said means comprising a-iirst connector member connected to 40. one of said conductors and a 'second connector 'member connected to the other of said conductors, a ported `recess in each connector member communicating with the channel in the conductor to which said connector member is attached, a casingi'or enclosing the parts oi the joint, a

unitary tubular insulator supported at its one end by the rst connector member and supported at its other end by the casing, said insulator surf rounding one end of said secondV connector member and defining an independent chamber within the main chamber oi the casing, said independent chamber communicating with the port of the recess of said second connector member, an externa.: conduit connected te seid independent chamber, a conduit oi' small cross-sectional area forming a helix-oi many tunis surrounding the first connector member and communicating with the port of the recess of said ilrst connector member and with the main chamber of the casing', a covering of insulation for both connector members and in which the helical conduit is located, and an external conduit connected to the main chamber of the casing. v2. In a cable ljoint of the character described, 0 the combination of a ilrst connector member havving a socket and a lateral port communicatingtherewith, a rst conductor having an insulating covering and having a central iiuid iilled channel, said conductor having one end located in the socket with its channelin communication with the port, a second connector member mounted in the ilrst member and also having a socket and a lateral port communicating therewith, a second conductor'having an insulating covering and 75.

v having a central fluid nlled channel, said second conductor having one end located in the socket of the second connector member with its channel in communication with the port thereof, said coninsulator and denning a part oi said casing, the insulator thus dividing the casing into a main chamber and an independent chamber, fluid being free to flow to'or from the channel of the first conductor, through the port of the iirst connec-v tor member into the independent chamber, a helical conduit of numerous turns surrounding the second connector member, communicating with 'the' lateral. port thereof and opening into the main chamber of the casing, and insulation applied over the helical conduit and 4one end of the insulator. 3.\In a cable joint of the character described, the combination of a first connector member having a conductor receiving socket and ported recess at one end and -a solid extension at the other; a secondconnector 'member having a socket at f one end receiving the extension of the first'connector member and having a conductor receiving socket and ported recess at its other end,

a metallic sleeve mounted on .the wall of the second connector member and extending longitudinally over a part of the first conductormember, a`pair of fluid filled conductor ends from which the insulating coverings have been stripped, one such conductor end being located in each of the conductor receiving sockets of themembers, a-

metal casing enclosing the parts of the joint, a conical insulator within the casing supported at its inner end by the sleeve and at its outer end by the casing and dividing the casing into a main chamber' and an independent chamber at one nd thereof, the latter communicating with the ported recess in the first connector member, said connector members interrupting the passage of uld from one conductor end to the other, in-

sulation wrapped around the second v"connector member, the sleeve and a. part'of the conical insulator, and a helically formed conduit of numerous turns embedded in the portion of the inl sulation covering the second connector member, which is in communication with the ported recess of the second member and with the interior of l the main chamber of the casing.

(4. In a cable joint of the character described*I the combination of a first connector member havinga socket and a ported recess at one end and a solid extension at the other, a hollow core uid filled cable conductor end located in the socket, the core communicating with the ported recess, a second connector member having sockets at both ends, in one of which is located said extension, the other of said sockets having a ported recess, a hollow core fluid filled cable conductorend located -in lthe last mentioned socket, the core communicating with the ported recess, said members electrically connecting the cables and preventing the flowl of fluid from one. to the other, an enclosing casing sealed at its ends to the conductor coverings, a metallic sleeve screw threaded to one end of the second connectonmember and surrounding a part of the extension of the nrst connector member, an insulator supported at its inner end by the sleeve, means form'ing'a part of the casing for supporting the outer end of the l insulator, Asaid insulator and its supports dividing the casing into a small and a large chamber, the small chamber being in direct communication with the port of the recess of the ilrst connector member, an insulating covering for both connector members, and a conduit means located in the insulatingfcovering and establishing comsecond connector member and the large chamber.

5. A joint for fluid filled cable comprising a first connector member having a rod-like exten-l sion at one end, Aand a socket at the other, a

, munication between the port of the recess of the hollow core iiuid filled conductor end located" within the socket, a second connector member having sockets on opposite ends thereof in one of which said extension is located. a second hollow fluid filled conductor having one end located in the other of said sockets, ports in the conductor end receiving sockets of the members in communication with the cores of the conductors, said connector members4 electrically connecting the `cable ends and preventing the flow of vfluid from one cable end into the other, a longitudinally extending tubular insulator which surrounds the socket of the first member, a metal sleeve supported by the second member which is in telescopic relation with respect to portions of the extension and th'e'first connector member and which engages and supports the inner end of the insulator, a chambered casing for the joint which also supports the outer end of the insulator, said insulator dividing. the chamber of the casing into two parts, one of which is in communication with the porty opening into the core ofone conductor and the other with the port opening into the core of the other conductor, and insulation which isrwrapped around the members and also around the inner end oi the tubular insulator. l

6. In a cable joint of the character described, the combination of a first connector member hav- -ing at one end a socket to receive thewires of cored cable, said connector member preventing the flow of fluid from one cable end to the other, a sleeve mounted on and supported by one end of the second member, a second sleeve mounted on and supported by the first mentioned sleeve and forming an axial extension thereof and surrounding a part of the first connector member, an insulator having its inner 'end located withinl one end of the second sleevey and supported externally thereby, a tubular metal member located inside of the insulator at the inner end thereof for supporting it'intemally, a casing enclosing parts of the Joint, and a means forming a part of the casing which supports the outer end of the insulator.

7. A combined feeding and nuid stop Joint comprising a first connector member having sockets at both ends, and a laterally opening ported recess located between the sockets, a first concess being in communication, a second connector menber having a rod-like extension at'one end fitted into a socket of thel first member and a socket at the'other end, and a laterally opening portedrecess located between the socket and the extension, a second conductor end having a. centrai core filled with fluid located in the socket of the second connector member, the core of the second conductor and the recess of the second connector member being in communication, the two members electrically uniting the conductor ends and preventing the flow of fluid from one to the other, a casing surrounding the members and cable ends and sealed to the coverings of said ends, a preformed insulator dividing the casing chamber into a large and a small chamber, the latter being located at one end o the casing and communicating with the ported recess of the s'econd cable connector member, a metallic means supported by the first-'connector member and surrounding a portion of the second con-y nector member in telescopic relation for supporting the inner end of the preformed insulator, a means supported by a wall of the casing for supporting the outer end of the preformed insulator, a. wrapping of insulating material around the first connector member, the turns of which are spaced to form an open helix of restricted cross-section, the helix being in free communication with the ported recess in the first connector member and also with the large chamber of the casing, and

a conduit means for feeding iiuid to and receivl5 ing it from said large chamber.

. PIERRA." 'IHIODORE CAPDEVILLE. 

